We're migrating to Kubernetes and many of our services are using Hystrix which expose a stream of server sent event data consumed by Turbine and visualized by a Hystrix Dashboard. I'd like to implement a service discovery plugin to Turbine which auto discovers our Hystix streams running on Kubernetes.
Would it be a good idea to use labels for this? I.e. define a label that includes the path to the hystrix stream for each pod using Hystrix?
If labels are not a good idea, what would be?
I had the same problem and I created a little project to address it.
essentially I implemented a hystric instance discovery class to work with kubernetes services.
You can find my project here.
This projects is in its infancy so bugs are likely. Feedback it welcome.
Thanks
Raffaele
How about making Hystrix a Kubernetes service?Kubernetes has two suggested ways to discover services: https://github.com/kubernetes/kubernetes/blob/master/docs/user-guide/services.md#discovering-services
Related
Hello intelligent stackoverflow people,
i am trying to deploy my microservice backend developed with nestjs on Kubernetes.
But i don´t know how to do it or even find a tutorial that shows me how to.
I found an article talking about a similar case using Kafka as the event-streaming-service.
https://limascloud.com/2022/03/22/nestjs-on-kubernetes-kubernetes-for-developers/
Instead of Kafka i used the native event based communication provided by the framework described in the docs. It is some basic topic based publish-subscribe mechanism.
Does that prohibit the use of Kubernetes. Do i need to use some kind of external communication software?
I am really confused at the moment and dont know if we/i made an error since the start.
I am the author of the post you mentioned. You should be able to use the event-streaming-service, but it's a different scenario than the one I represent in the post.
In the post, the pods are connecting to a Kafka service that is running outside of the Kubernetes network, but in your scenario, the pods need to be able to connect to one another inside the Kubernetes network.
If you are planning to use two separate services, I would recommend using an external broker. If you plan to use the default mechanism, make sure to set the host and port configuration for one of the pods. Lets say api is just going to produce, so set its configuration to the pod name and port of the worker. Let me know if it works. I would start trying to make it work on your local env before going to Kubernetes.
I've got some doubts about deploying Spring Cloud Gateway (old Zuul) with Kubernetes and getting zero-downtime. I'm completely new to Kubernetes and I'm a bit lost with quite a lot of concepts.
We would like to use the Spring Cloud Gateway verify the JWT. I've also read that when I've got a call, it should go first have gateway, afterwards the ribbon discovery and finally the REST services.
The application has very strict zero-downtime requirements. My question is, what happens when I need to redeploy for some reason the Gateway? Is it possible to achieve the zero-downtime if it is my first component and I will have constantly traffic and request in my system
Is there any other component I should set-up in order to archive this? The users that are having having access to my REST services shouldn't be disconnected abruptly.
Kubernetes Deployments use a rolling update model to achieve zero downtime deploys. New pods are brought up and allowed to become ready, then added to the rotation, then old ones are shut down, repeat as needed.
Context
I am deploying a set of services that are containerised using Docker into AWS. No matter which deployment solution is chosen (e.g. raw EC2/ECS/Elastic Beanstalk/Fargate) we will face the issue of "service discovery".
To name just a few of the options for service discovery that I've considered:
AWS Route 53 Service Registry
Kubernetes
Hashicorp Consul
Spring Cloud Netflix Eureka
Specifics Of My Stack
I am developing Java Spring Boot applications using Spring Cloud with the target deployment environment being AWS.
Given that my stack is Spring based, spring cloud eureka made sense to me while developing locally. It was easy to set up a single node, integrates well with the stack and ecosystem of choice and required very little set up.
Locally, we are using docker compose (not swarm) to deploy services - one of the containers deployed is a single node Eureka service discovery server.
However, when we progress outside of local development and into staging or production environment we are considering options like Kubernetes.
My Own Assessment Of Pros/Cons
AWS Route 53 Service Registry
Requires us to couple code specifically to AWS services. Not a problem per se, we are quite tied in anyway on other parts of the stack (SNS/SQS).
Makes running the stack locally slightly more difficult as it relies on Route 53, I suppose we could open up a certain hosted zone for local development.
AWS native, no managing service registries or extra "moving parts".
Spring Cloud Eureka
Downside is that thus requires us to deploy and manage a high availability service registry cluster and requires more resources. Another "moving part" to manage.
Advantages are that it fits into our stack well (spring ecosystem, spring boot, spring cloud, feign and zuul work well with this). Also can be run locally trivially.
I presume we need to configure the networks and registry zone to ensure that that clients publish their host address rather and docker container internal IP address. e.g. if service A is on host A and wants to talk to service B on host B, service B needs to advertise its EC2 address rather than some internal docker IP.
Questions
If we use Kubernetes for orchestration, are there any disadvantages to using something like Spring Cloud Eureka over the built in service discovery options described here https://kubernetes.io/docs/concepts/services-networking/service/#discovering-services
Given Kube provides this, it seems suboptimal to then use eureka deployed using kube to perform discovery. I presume kube can make some optimisations that impact avaialbility and stability that might nit be possible using eureka. e.g kube would know when deploying a new service - eureka will have to rely on heartbeats/health checks and depending on how that is configured (e.g. frequency) this could result in stale records whereas i presume kube might not suffer from this for planned service shutdown/restarts. I guess it still does for unplanned failures such as a host failure or network partition.
Does anyone have any advice on this, do people use services like Kubernetes but use other mechanisms for service discovery rather than those provided by kube. Is there a good reason to do one or the other?
Possible Challenges I Anticipate
We could replace eureka, but relying on Kube to perform discovery will mean that we need to run kube locally to deploy whereas currently we have a simple tiny docker-compose file. Also, I'll have to look at how easy it'll be to ensure that ribbon, zuul and feign play nicely with this.
Currently we have ribbon configured with a eureka client so that service A can server to service B just as "service-b" for example and have ribbon resolve a healthy host via a eureka client. I guess we can configure ribbon to not use eureka and use an external Kube service name which will be resolved by Kube DNS at runtime...
Final Note
Thanks in advance for any contribution or advice. I know this might elicit a primarily opinion focused response. But I am hoping someone can provide objective guidance on when one solution might be preferable to another.
Service discovery is something you get out-of-the-box with Kubernetes. So having another external service in your platform will be another application to maintain, deploy and can be a point of failure. So I would stick with the the service discovery provided by Kubernetes.
In this question, I managed to set-up REST communication between two microservices using a user-defined bridge network in docker-compose
Now, I'm trying to do the same when hosting my microservices on AWS.
I could really use some pointers as to how to achieve this, because I'm terribly lost.
I've tried following numerous tutorials, both written and on pluralsight, but none seem to be close enough to my use case.
My project architecture is as follows:
https://i.stack.imgur.com/vc6TX.png
And my project infrastructure should probably look like this:
https://i.stack.imgur.com/X73HA.png
Thanks
You can use internal Loadbalancer for each service and create DNS records us it for app communication Also ECS and a service discovery feature that is useful in this scenario.
I am trying to figure out how to best collect metrics from a set of spring boot based services running within a Kubernetes cluster. Looking at the various docs, it seems that the choice for internal monitoring is between Actuator or Spectator with metrics being pushed to an external collection store such as Redis or StatsD or pulled, in the case of Prometheus.
Since the number of instances of a given service is going to vary, I dont see how Prometheus can be configured to poll those running services since it will lack knowledge of them. I am also building around a Eureka service registry so not sure if that is polled first in this configuration.
Any real world insight into this kind of approach would be welcome.
You should use the Prometheus java client (https://www.robustperception.io/instrumenting-java-with-prometheus/) for instrumenting. Approaches like redis and statsd are to be avoided, as they mean hitting the network on every single event - greatly limiting what you can monitor.
Use file_sd service discovery in Prometheus to provide it with a list of targets from Eureka (https://www.robustperception.io/using-json-file-service-discovery-with-prometheus/), though if you're using Kubernetes like your tag hints Prometheus has a direct integration there.